Legacy Endress+Hauser Instruments: Identifying, Supporting and Replacing FMR231, Prowirl 72F, Cerabar S PMP71, Levelflex M FMP40 and Other Older Models

A large share of the field instruments on gas plants, water networks and utilities commissioned in Oman between roughly 2000 and 2015 are Endress+Hauser: Micropilot M radars, Levelflex M guided wave radars, Prowirl 72 vortex meters, Promag 50/53 magmeters, Promass 80/83 Coriolis meters and Cerabar S/Deltabar S transmitters. Many still work well, but when one fails the maintenance team searches for an old model number and finds it has been superseded. Handling Endress+Hauser legacy instruments well means knowing what you have, deciding between a spare and an upgrade, and recommissioning the replacement so the loop behaves as before. This guide covers each step.

Start With the Nameplate: What to Record

The model name alone, for example “FMR231” or “Prowirl 72F”, is not enough to order anything. E+H instruments are defined by a full order code in which each position encodes an option: approval, process connection, material, antenna or sensor type, output, display and housing. Record the following before raising a requisition:

• Order code (the full alphanumeric string after the model name) and, where present, the extended order code.
• Serial number. E+H’s online device information tools can usually return the original order code and documentation from the serial number, which helps when a nameplate is weathered.
• Ex marking and certificate number, if the instrument is in a hazardous area.
• Process connection: flange standard, size and rating, thread, or hygienic fitting.
• Wetted materials and seals.
• Output and communication: 4–20 mA HART, PROFIBUS PA, FOUNDATION Fieldbus, pulse/status outputs.
• Power supply: loop-powered two-wire or four-wire mains/DC.
• Measuring range and calibration data, especially for pressure and DP transmitters.
• Tag number and the current configuration, saved via the display, a handheld or FieldCare/DeviceCare if the instrument still communicates.

Photograph the nameplate and the installation (nozzle, flange, cable entry) before removal. These photographs answer most questions that come back from the supplier.

Generations: Old Families and Their Current Counterparts

E+H has moved through several platform generations. The table summarizes the transitions most often met on Omani sites. Where the successor depends on the specific configuration, E+H selects it from the full order code, so confirm with the order code before ordering.

Level instruments

The Micropilot M FMR231 is a rod-antenna radar frequently found on chemical dosing and corrosive liquid tanks. Its newer counterparts include the 80 GHz Micropilot FMR60, which has a narrow beam that copes better with nozzles and internal obstructions, and compact two-wire radars such as the Micropilot FMR20 for simpler water and wastewater duties. The beam angle, nozzle requirements and process connection differ, so treat the change as a re-specification. For background on radar choice, see the radar level transmitter selection guide.

The Levelflex M FMP40 guided wave radar maps to the Levelflex FMP51 family for most liquid applications, with FMP54 used for high-pressure and high-temperature duties. Probe type (rod, rope, coax), length and centring must be re-specified rather than copied from memory.

Flow instruments

The Prowirl 72F flanged vortex meter is common on steam, gas and utility lines. Its replacement comes from the Proline Prowirl 200 family. Magmeters such as the Promag 50P move to the Proline generation, for example the Promag P 500 for chemical and process duty or the Promag W 10 for water. The Promass 80F Coriolis meter is typically replaced by a Proline Promass such as the Promass F300.

For any inline flowmeter, check face-to-face length, flange standard and rating, and grounding arrangement. If the new meter’s installed length differs, the spool must be modified, which turns a one-hour swap into a work package with hot work or a shutdown.

Pressure and analysis

The Cerabar S PMP71 is replaced by the Cerabar PMP71B, and the ceramic-diaphragm PMC71 by the Cerabar PMC71B. The Deltabar S PMD75 has its successor in the Deltabar PMD75B. Liquisys M transmitters such as the COM223 dissolved oxygen unit are replaced by the Liquiline CM442, which uses digital Memosens sensors; confirm whether existing analog sensors can be retained or must be replaced at the same time. The pressure transmitter selection guide covers range and diaphragm choices in more depth.

Like-for-Like Spare or Upgrade

A legacy model may still be obtainable new, refurbished or as surplus, and some spare electronics modules remain available for a period after a product is discontinued. The right choice depends on criticality, remaining plant life and how much engineering the change triggers.

When buying a like-for-like legacy unit, insist on the full order code match and check the firmware version against what your DD/DTM library supports.

What Changes When You Replace

• Process connection and dimensions: flange rating, face-to-face length, nozzle height, antenna or probe length.
• Electronics and output: two-wire versus four-wire supply, HART revision, fieldbus profile, additional outputs.
• Ex approvals: the new certificate must suit the zone, gas group and temperature class, and the loop entity parameters must be rechecked for intrinsically safe loops.
• Device description files: the DCS, handheld and asset management system need the correct DD or DTM for the new device and HART revision.
• Configuration: parameters do not transfer automatically between generations; they must be re-entered and verified.
• Cable entries: thread type and gland size may differ.

Recommissioning the Replacement

Level

For radar and guided wave radar, enter tank geometry (empty and full distances, or reference height), medium properties and the application profile. Perform an interference echo suppression (mapping) with the tank as empty as practical so nozzle and internal echoes are suppressed. Verify the reading against a manual dip or sight glass at two levels.

Pressure and differential pressure

Configure the range, damping and units, then perform a zero trim at operating static pressure for DP transmitters by equalizing the manifold. For gauge transmitters, zero with the process isolated and vented. Record as-left values in the calibration system.

Flow

Transfer or enter the calibration factor (K-factor for vortex, calibration factor and zero point for magmeters and Coriolis meters) from the new meter’s calibration certificate, not the old one. Set pulse value, totalizer units and low flow cut-off. For Coriolis meters, perform a zero verification under no-flow, full-pipe conditions after the meter has reached process temperature. Record as-found and as-left data so the replacement has a traceable baseline.

Oman Considerations

Instruments in Oman often sit in direct sun with ambient temperatures of 45–50 °C. Electronics inside a sealed housing run hotter still, so fit sun shades and check the ambient rating of the replacement. Coastal plants in Sohar, Sur, Duqm and Salalah see salt-laden humidity that attacks aluminium housings and cable glands; consider stainless steel housings for exposed coastal duties. Shipping times for specific order codes can be long, so critical instruments with no installed redundancy justify a held spare, configured and tagged in advance where possible.

Common Mistakes

• Ordering from the model name only. Two FMR231 or PMP71 units can differ in antenna, process connection, range, material and approval, and the wrong option code is usually discovered at the nozzle.
• Copying the old configuration blindly. Parameter names, defaults and damping behaviour differ between generations; check each value against the new manual.
• Reusing the old calibration factor on a new flowmeter. Each meter body has its own factor on its calibration certificate.
• Skipping echo mapping after a radar swap, then chasing false high levels caused by nozzle or agitator echoes.
• Forgetting the IS loop calculation. A new transmitter with different Ci or Li values can push an intrinsically safe loop outside its barrier parameters.
• Leaving the DCS on the old device description, so diagnostics and some parameters are unavailable to operators and asset management.

Replacement Checklist

• Photograph nameplate and installation; record full order code and serial number.
• Back up the existing configuration if the device still communicates.
• Identify the current-generation counterpart and confirm with the full order code.
• Compare process connection, dimensions, materials and seals.
• Confirm Ex certificate, ambient temperature rating and IS entity parameters.
• Load the correct DD/DTM into the DCS, handheld and asset management system.
• Plan recommissioning: echo mapping, zero trim or calibration factor entry.
• Update loop drawings, datasheets and the spare parts list.

Sourcing Legacy and Current E+H Instruments Through Seven Star LLC

Seven Star LLC supplies Endress+Hauser instruments for plants in Oman and the GCC, including legacy models where they can be sourced and current-generation replacements. Browse the Endress+Hauser brand page and send the full order code and serial number from the nameplate so the request can be matched accurately.

Send the full order code from your Endress+Hauser nameplate to Seven Star LLC for a like-for-like spare or a matched current-generation replacement.